The invention relates to a joint connection between two plastic parts, wherein one part is at least partly rotatable in relation to the other part.
As state of the art, such a construction is already known. For example, West German Printed Disclosure 3,014,578 shows a structure in which the two plastic parts, one of which is designed as a bearing part and the other as clamping jaw halves, are joined together through a joint connection in the form of a short one-piece short hinge strip. A disadvantage in this prior art construction, which uses a hinge strip as the joint connection, is the danger of breaking the hinge. In case of hard materials this danger is considerable when bending through the required bending range of about 90.degree.. There is also the disadvantage of having a dependence on material of the film hinge. That is, the whole construction must be adapted to the shape of the hinge to achieve the desired elasticity.
In a so-called two-component injection molding process, there is a further disadvantage that a material must be used which is adapted to the shape of the hinge part.
As an alternative to this known state of the art, it is generally been known to produce two plastic parts singly and then assemble them together. In which case, however, high production and single parts costs result. For this type of construction, two dies are needed for the production of the corresponding parts, as well as different bearing holding devices. Additionally, the two parts must be assembled together in order to have a unit ready for use.
The present invention attacks the problem of designing a construction of the kind mentioned so that without regard to the material, an improvement of the hinging between two plastic parts can be provided with simpler and less expensive production.
This problem is solved, according to the invention, by the fact that the joint connection consists of a shell-form outer element on the one plastic part and an inner element, at least partly supported in the outer element, on the other plastic part. Further, the two elements are made by injection molding one inside the other, in a single die. In this way, the advantage is given of a simple and costsaving production, as a result of the use of a single die in the joint zone. The two plastic parts are, however, joined together movably through the joint zone. Since between the two plastic parts there is no connection in the form of a hinge, there is, advantageously, no longer any danger of breaking at the turning point. Moreover, for the joint connection according to the invention, there is no dependence on specific material characteristics or properties. The joint connection is ideally suited to hard materials. Furthermore, through the joint connection of the invention with the loose connection between the one and the other plastic part, a rotation range of up to 360.degree. can be reached.
Since for the joint connection according to the invention, there is no dependence on material, the best materials can be used in each case, especially in a two-component injection molding process, which make possible a good adhesion between the first and the second components.
If the joint connection according to the invention is to absorb greater forces, this can be achieved at any time by increasing the thickness dimensions of the inner and outer elements.